The invention described herein was made by an employee of the United States Government, and may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.
1. Field of the Invention
This invention relates generally to spacecraft and, more particularly, to systems and methods for determining a spacecraft orientation.
2. Description of Related Art
Satellite applications typically require knowledge of the satellite orientation or attitude. For example, a communication satellite may be required to point a radio antenna at a particular ground station. If the satellite orientation is wrong, the radio signal may miss the ground station.
Many satellites use star sensors to determine their orientation by processing positions of identified stars in the fields of view of the sensors. This process typically requires an initial determination, or estimate, of the satellite orientation.
It is an object of the present invention to provide systems and methods of determining or estimating an orientation of a spacecraft. According to an aspect of the present invention, there is a method for operating with a spacecraft and a first signal, the first signal including star position data. The method comprises generating a second signal in the spacecraft, the second signal including star observations; processing the first and second signals; generating a third signal responsive to the processing step; displaying the third signal; viewing the displayed third signal; responsive to the viewing step, generating a fourth signal; and processing the fourth signal to determine an orientation of the spacecraft.
According to another aspect of the present invention, there is a system for operating with a first signal including star position data and a spacecraft having a generator that generates a second signal, the second signal including star observations. The system comprises a first processor that processes the first and second signals to generate a third signal for display; and a second processor that receives a fourth signal, identifying features in the third signal, and processes the fourth signal to determine an orientation of the spacecraft.
According to yet another aspect of the present invention, there is a system for operating with a spacecraft and a first signal, the first signal including star position data. The system comprises means for generating a second signal in the spacecraft, the second signal including star observations; means for processing the first and second signals; means for generating a third responsive to the processing means; means for receiving a fourth signal identifying features in the third signal; and means for processing the fourth signal to determine an orientation of the spacecraft.